The phase interface process is generally known from the literature and is described, for example, in EP-A 517 044.
The polycarbonates prepared in this way have a more or less high content of carbamate compounds, which leads to a defective structure and therefore to a loss in the quality of the carrier material for optical storage media, such as CD, DVD or the like.
Calibration is carried out by an external standard method (multiple point calibration).
The object was therefore to develop a process, preferably a continuous process, for the preparation of polycarbonates which leads to polycarbonates having a low content of carbamate compounds and therefore to a significantly increased yield of high-quality optical storage disks.
Polycarbonates which contain a relatively high content of carbamate compounds after hydrolysis of the carbonate groups are a disadvantage for the production of optical storage media, in particular writable optical storage media, since the yield falls as a consequence of non-uniform application of the information-carrying layer, usually dyestuffs. It was furthermore found that audio-CDs and DVDs disks stick together in the course of production usually even before the coating.